Abstract
Anal endosonography was performed in 17 patients, aged 7 to 18, after surgical correction of anorectal malformations. Ten of the 17 had high type, 5 had intermediate type, and 2 had low type anomalies. They had the transverse images for the anal canal and the images were obtained at 5cm, 4cm, 3cm, 2cm. and 1cm from the anal verge, respectively. In the low type anomaly, external and internal anal sphincters were visualized as hyperehcoic band and hypoechoic band, respectively. However, 1 of the 2 showed a partial defect of the internai sphincter after anal transposition. In the intermediate type anomaly, the external anal sphincter was observed as a hyperechoic band in all of the 5 patients. However, the border or its echo level was unclear. And the internal sphincter could not be observed. In the high type anomaly, the hyperehoic band was observed in all of the 10 patients. However, its border or the echo level was not clear. In addition, the presence of external sphincter muscle in the high and the intermediate type anomalies was less remarkable than that in the low type anomaly. As for the presence of internal sphincter muscle, 5 of the 10 with high type anomaly showed a presence of the internal sphincter muscle and other 5 did not.
